PTH and chronic kidney disease: Tertiary hyperparathyroidism (THP) is, most commonly, the outcome of longstanding secondary hyperparathyroidism (SHP) due to chronic kidney disease and is defined as the autonomous and excessive secretion of parathyroid hormone (PTH) by the parathyroid glands, leading to persistent hypercalcemia and elevated PTH serum level, which values do not decrease even when the underlying renal disease is resolved, usually after a renal allograft [1].